Effect of exclusion policy on the control of outbreaks of suspected viral gastroenteritis: Analysis of outbreak investigations in care homes

Background: Norovirus is an important cause of gastroenteritis outbreaks in care homes. Differences exist in the recommended duration of exclusion for affected staff during an outbreak. Methods: We conducted a retrospective analysis of outbreak reports in 2006 and 2007 managed by health protection staff in 2 counties with differing exclusion policies, one advising exclusion of affected staff and isolation of residents for 72 hours and the other for 48 hours after the resolution of symptoms. We compared attack rates and average numbers of cases in residents and staff, adjusting for type of care home and staffing rate. Results: A total of 96 outbreaks were managed, 63 with a 72-hour exclusion policy and 33 with a 48-hour exclusion policy. The longer exclusion policy resulted in lower mean number of cases among staff (6.5 vs 9.6; P = .044) and a lower overall attack rate (32.6% vs 35.1%; P = .05). No differences in the mean number of cases or the attack rate among residents were seen. Conclusion: This brief study suggests that a longer exclusion policy reduces the number of cases among staff affected with viral gastroenteritis, possibly resulting in less staff absences. This could have potential benefits, particularly when resources are limited.